How do Hybrids work? Newbie questions encouraged!
Have you ever wondered how hybrids work? What is the technology behind them? What is the difference between Toyota's Prius and Honda's Insight? Here is the place to ask your questions.
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http://www.edmunds.com/ownership/techcenter/articles/45188/articl- e.html
Insight Civic and Accord = IMA = serial hybrid
Silverado/Sierra = ? = starter/generator control module
A serial hybrid uses the engine to run the batteries, and has only electric propulsion. At least that is my understanding.
I think the Honda IMA is a parallel system, because both the ICE and electric motors are engaged at the same time.
however howstuffworks.com and Insightcentral.net http://www.insightcentral.net/encyclopedia/enhybrid.html say what you are saying and that is IMA is a parallel system, if you ask me (and others) IMA is just that integrated motor assist, it (the IMA electric motor) is in series with the gas motor, the vehicle can't move without the gas motor thus its a serial hybrid. Prius / Escape can use either or both thus a parallel hybrid.
http://auto.howstuffworks.com/hybrid-car2.htm
"You can combine the two power sources found in a hybrid car in different ways. One way, known as a parallel hybrid, has a fuel tank, which supplies gasoline to the engine. But it also has a set of batteries that supplies power to an electric motor. Both the engine and the electric motor can turn the transmission at the same time, and the transmission then turns the wheels."
Note that both Honda and Toyota hybrids fit this definition, though many Prius enthusiasts insist that the planetary gearset does not meet the qualification of a transmission. But it powers the wheels, so cut some slack here... the two terms refer to how the electric motors are used.
"By contrast, in a series hybrid the gasoline engine turns a generator, and the generator can either charge the batteries or power an electric motor that drives the transmission. Thus, the gasoline engine never directly powers the vehicle."
Emphasis is mine...
Many Prius enthusiasts make their own definitions, based on the difference in the HSD, but that doesn't change the scientific literature. In implementation, the HSD does have the electric and ICE operating at the same time (different parts of the planetary gearset), and in the IMA the electric is in line with the transmission. This causes some confusion. I suppose that is why we have this forum...
Just to claify for the newbies:
The IMA (Honda Hybrid) can move with or without the electric motor, at any speed, since the ICE is used at all times. It won't perform so well or get very good MPG though.
The HSD (Toyota Hybrid) cannot move without the electric motor - battery power is all it uses up to about 15 MPH. At least, I've never seen any Prius enthusiasts claim it will move from a standing start with ICE only.
I figured you'd probably catch that. No, not really, though I haven't ever caught them in a factual mistake (I've only checked the automotive stuff). I suppose I should have said "reliable" or "known factual" source.
"do note that the Prius can move without its electric motors and to say thats all it uses up to 15 MPH is just plain wrong, I don't know where you heard that but ask that source if the ICE ever runs when they are in reverse or at slow speeds (yes it does thus the parallel label, it can ((and does)) use either or both motors as needed)))"
Can you please quote me a "reliable" and "factual" source that says the Prius can start up from a standstill on ICE only? The ICE engine will engage at low speeds - to charge the batteries and power the electric motors. At least that is my understanding of the system from the Toyota web sites, which include some very nice animated graphics of the HSD system.
It's only a side note anyway, since both IMA and HSD are not designed to work ICE only.
“The hybrid scooter's internal combustion engine and direct rear-wheel-drive electric motor function in two distinct modes. In series mode, when riding on flat ground and when high output is not required, the engine alone powers the electric motor. In parallel mode, used during acceleration and when high output is required, the electric motor assists the engine. ”
Based on this description, Insight and Civic Hybrid would qualify as Parallel Hybrid since IMA is an assist system. HowStuffWorks seems to describe it in a similar way.
BTW, Honda FCX utilizes Fuel Cell Stack to help keep the ultra capacitor pack charged (no batteries in this case). This charge in the ultra capacitors is used by the electric motor to drive the vehicle.
Technically
Series: One source transforms energy into a form that is utilized by another source to drive the vehicle (a “series flow”).
Parallel: Multiple sources are used to drive the vehicle at the same time (in parallel). IMA or any assist mode hybrid would be a parallel hybrid.
IMA also operates in series mode when necessary. Rolling down a hill, or when batteries need to be recharged, the electric motor doesn’t assist the ICE, but sends energy to recharge the battery pack.
No offense, but that is totally incorrect.
The limit for electric drive is 10kW.
If you exceed 10kW, which usually happens when accelerating, the engine starts up.
Cruising doesn't require that much electricity. So you actually can sustain speeds up to 42 MPH. And there is typically enough battery power available to do that for a mile or 2. Under ideal conditions, you can drive up to 3 miles using the battery.
Then, it only takes about 10 minutes of driving at speeds above 42 MPH to replenish the charge-level to cruise on electricity for awhile again.
> At least, I've never seen any Prius enthusiasts claim it will move from a standing start with ICE only.
That's true... since HSD wasn't designed to do that. 100 percent of the time thrust is being sent to the wheels by the engine, electricity is also being generated. Remember, the A/C, steering, 2 small heaters, and many of the accessories (like the lights) require that electricity to run anyway.
JOHN
I realize, as I said before, that it is a moot point for the HSD, since it wasn't designed for that mode.
The system has quite a few protective mechanisms preventing that from ever happening.
JOHN
Unless there is more than just a remote possibility of it actually ever happening, discussing it doesn't have a point.
In other words, there is a higher statistical chance of being in an accident. So why focus on someless even less probable?
JOHN
But, my point was to bring out a scenario where electric supply fails for a moment. Would the gasoline engine be able to move Prius by itself?
Now, should the "electrical system" fail, what can you expect? Your car is broken. I speculate (though certainly can't confirm) that you can't drive because the car has an eCTV (electronically-controlled continually variable transmission). This isn't something to worry about, though. We're not talking artificial intelligence here, capable of destructing the world if it gets out of control... it's still a car. You should be more worried about a flat tire.
If valid, this would answer stevedebi’s question.
Should you decide you're not giving Shell one more cent of your money and run out of gas, the batter and motor are capable of propelling you for a short distance. Of course, this isn't good for the car but I have heard stories of Prius owners gliding into the gas station in purely electric mode.
No, it doesn't really. I still think his question is about the equivalent to "If the gas all of a sudden magically disappears from the tank of my F-150..."
Hmmm, considering the MPG of the F150, doesn't gas always magically disappear from the tank. You look down at the dash and - WHAM - there is the low fuel light...
How a Honda employee bakes a potato:
Preheat new, high-quality oven to 350 F. Insert Idaho potato. Go do
something productive for 45 minutes. Check for doneness, and then remove
perfectly baked potato from oven and serve.
How a GM employee bakes a potato:
Instruct an Idaho potato supplier to preheat the oven to 350 F. Demand that
the supplier show you how he turned the dial to reach 350F, and have him
come up with documentation from the oven manufacturer proving that it was
calibrated properly. Review documentation, then have supplier check the
temperature using sophisticated temperature probe. Direct supplier to
insert potato and set timer for 45 minutes. Have supplier open oven to prove
potato has been installed correctly, and request a study proving that
45 minutes is the ideal time to bake a potato of this size.
Check potato for doneness after 10 minutes.
Check potato for doneness after 11 minutes.
Check potato for doneness after 12 minutes.
Become impatient with supplier (why is this simple potato taking so long to
bake?). Demand status reports every five minutes. Check potato for doneness
after 15 minutes... After 35 minutes, conclude that potato is nearing
completion. Congratulate supplier, and then update your boss on all the
great work you've done, despite having to work with such an uncooperative
supplier. Remove potato from oven after 40 minutes of baking, as a cost
savings; without loss of function or quality versus the original 45 minute
baking time. Serve potato.
Wonder aloud what on earth those Japanese folks are doing over there to make
such good low-cost baked potatoes that people seem to like better than GM
potatoes.
Daimler Chrysler's Baked Potatoes:
Design great looking potato. Include sour cream, bacon bits, chives, and
cheese. Bean counters then create MCM system. Engineers spend 2 years
looking for ways to take out sour cream, bacon bits, chives, and cheese.
Engineers find cheap imitation chives from Japanese supplier. Management
commands engineers to use expensive, over-engineered German bacon bits to
help prop up weak German suppliers. Sell potato with cheap imitation chives,
no sour cream, cheese or expensive German bacon bits. Potato rots so fast
customer swears never to buy another DCX potato.
Ford's Baked Potatoes:
Engineers create plain looking, "everyman" potato. Sold as "green"
alternative to French Fries. When micro waved, potato explodes, causing
death and injury to customers and bringing end to 100-year potato and
butter-supplier relationship, lawyers flourish.
___You mean mine doesn’t have a cute little squirrel in one of those round cages chasing its tail going roundy roundy? I guess I had better open the hood and see what is actually underneath it
___Good Luck
___Wayne R. Gerdes
Well, I was assuming it was a gas + electric stove being used to bake the potato...
RyanT
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Are there quantitative differences in regeneration between a) coasting; b) braking, and c) coasting in "B"? Also, when the display indicates that the ICE is supplying power to the wheels and also recharging the battery, is this a different level than the three modes mentioned above?
Thanks for any clarification.
jprice
Since the "electric assist" of the Prius drive system is in fact an integral part of the drivetrain (unlike Honda IMA which is only supplemental) were the electric drive to fail, the car is basically out of operation. However, because the designers realized the critical nature of the electronic componentry of the THS/HSD system they took a lot of pains to make it as robust as possible.
With the power split device, if you don't have control over the rotation of the motor/generators you don't have the ability to modulate the effective gear ratio of the drivetrain. So a better comparative question to ask is would your F-150 run if the transmission were to suddenly seize up or lose its fluid?
In "motor" mode, the electric motor is providing torque to the wheels to turn. Now when you have to stop in a vehicle without regenerative braking, you must apply brakes sufficient to counter the torque (and energy is lost in the form of heat).
With regenerative braking, the electric motor now becomes a generator (role reversal), converting mechanical energy to electrical energy. Some of the torque from the turning wheels now drives the generator which manages to capture some of the overall energy into useful form (electric charge). For the rest, you would still need to use conventional brakes.
Regenerative braking simply reduces energy lost by minimizing the need for conventional braking (as much as possible).
___Except under a given higher then normal brake pedal pressure in which all Regenerative braking is overridden to allow ABS (Anti-lock Brakes) in the case of the HCH (Honda Civic Hybrid) and Insight, ABS, EBD (Electronic Brake Force Distribution), and TC (Traction Control) in the case of the AH (Accord Hybrid), and ABS, EBD, TC, VSC (Vehicle Stability Control), and BA (Brake Assist) in the case of the Prius II if so equipped.
___Good Luck
___Wayne R. Gerdes
This brings up an interesting perspective. Why would regenerative braking be overridden for ABS? ABS should be independent of the transformation of electric motor into an electric generator and monitor/impact wheel lockup during braking.
Why would regenerative braking be overridden for ABS? ABS should be independent of the transformation of electric motor into an electric generator and monitor/impact wheel lockup during braking.
___The lowest rotational speed of any/all wheels during an impending ABS or other safety function is probably to slow or switching so fast from impending lockup to release and back again for regen to recover anything anyways so it’s best to remove the Regenerative braking functions for safety purposes. I am sure the engineers that designed the various regen and assist systems were given a design basis that under any emergency, all regen and assist functions are not to interfere with the safety engineered functions in any way shape or form. This is the case with the Insight and I have not read of anything different with the HCH, AH, or Prius II yet.
___I have read of future hybrid electric drives that will control all safety functions vs. locked out as is the case today. If the electric drives were designed to switch this fast, they probably could but I don’t think we are ready for brake by wire and electrics just yet ;-) In the case of the Insight, the transition from regen to release or assist or assist to regen isn’t nearly fast enough for any emergency braking condition in my experience. The HCH, AH, and Prius should have improved upon this but the electrics are asked to perform a huge task to switch from regen to release and back so many times a second for such little M/G sets that it makes sense to me to leave them out of the equation.
___Good Luck
___Wayne R. Gerdes
Unless this has anything to do with reliability issues of the overall system (not so smooth deceleration), I don't see a point in ABS overriding regenerative braking.
Unless this has anything to do with reliability issues of the overall system (not so smooth deceleration), I don't see a point in ABS overriding regenerative braking.
___I guess you had better take that up w/ the 1000’s of engineers that work on the hybrid programs at Ford, Honda, and Toyota then.
___Good Luck
___Wayne R. Gerdes
In fact, I firmly believe that it would be possible to integrate ABS and regenerative braking by completely eliminating the involved hydraulics. It is not the electrical systems that are slow, quite the opposite from what you suggested earlier. “Speed”, which should translate to smoothness and effectiveness, would be an advantage with electrical/integrated system.
The way I see it, potential of slow reaction/action time from hydraulics may be to blame if there is an exclusion involved in all regenerative systems from ABS. If true at the moment, this may be a non-issue in the future where electric motors may control ABS. And not just ABS, but AWD system itself could see mechanical systems giving way to electro-mechanical systems (for the very same reasons). In case of AWD, we already see a few systems around.
___It is possible and I have already stated that many of today’s safety functions will be integrated into the Hybrid drivetrain but they are not today in the case of the Honda’s and probably not the Toyota.
___Good Luck
___Wayne R. Gerdes
The question however is, besides (relatively) slow response of hydraulic systems (which translates to non-linear deceleration), I don't see a reason why ABS/regenerative systems couldn't exist. But then, I don't know everything. Perhaps someone here does.
The question however is, besides (relatively) slow response of hydraulic systems (which translates to non-linear deceleration), I don't see a reason why ABS/regenerative systems couldn't exist.
___Have you ever driven a hybrid? If you have, you must have missed the non-linearity of regen braking. If you haven’t, they why bother making suppositions?
___Good Luck
___Wayne R. Gerdes
We're talking about tiny fractions of a second. You're not going "to feel it" simply by driving a vehicle. System is much faster than we humans can perceive/experience things.